The historically high water levels in Lake Ontario this year have threatened homeowners, municipalities and nuclear power plants - almost triggering emergency action at the Nine Mile Point Nuclear Facility in Oswego County.

Nuclear power plants are required by the federal government to follow security protocols if natural hazards, like flooding, put the facility in danger. According to the Nuclear Regulatory Commission (NRC), Lake Ontario was only a foot short of placing Nine Mile in the lowest-level emergency action plan.

Despite the close call, the plant's owner Exelon did not feel the situation warranted the unusual event status because the high water levels were not threatening operations. So the company appealed for a change.

"The company wanted to find a way to respond to that and not have to go into a situation where they were being faced with being in an unusual event status that really wasn’t warranted and furthermore a status that they could end up in that situation for quite some time because it can take a significant period of time for water levels to go back down," said NRC spokesperson Neil Sheehan.

The proposed amendment was approved. The new lowest-level emergency action plan will be triggered if there is a flooding around the plant that would prohibit plant staff from accessing the site in their vehicles. It will also apply to Exelon's other nuclear plant in Oswego County, Fitzpatrick.

"We want these emergency action levels to reflect actual emergencies as opposed to a condition that was not foreseen when they were developing these levels," Sheehan said.

FitzPatrick spokesperson Tammy Holden says this change is more specific and directly tied to plant operations.

Rising water levels can flood a nuclear plant's pumps, which are part of the system that keeps its reactors at a safe temperature.